1. Field
A positive active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same are disclosed.
2. Description of the Related Art
A rechargeable lithium battery has recently drawn attention as a power source for small portable electronic devices. It uses an organic electrolyte solution and thereby, has twice as high discharge voltage as a related art battery using an alkali aqueous solution and accordingly, has a high energy density.
This rechargeable lithium battery is used by injecting an electrolyte into an electrode assembly including a positive electrode including a positive active material that can intercalate and deintercalate lithium, and a negative electrode including a negative active material that can intercalate and deintercalate lithium.
For the positive active material, a composite metal oxide such as LiCoO2, LiMn2O4, LiNiO2, LiNi1−xCoxO2 (0<x<1), LiMnO2, and the like has been used. LiNiO2 among the positive active materials has high charge capacity but is difficult to synthesize, while an Mn-based active material such as LiMn2O4, LiMnO2, and the like is easy to synthesize, relatively inexpensive, and less of an environmental contaminate; but LiMnO2 has small capacity. In contrast, LiCoO2 shows electrical conductivity of about 10−2 S/cm to 1 S/cm at room temperature, high battery voltage, and excellent electrode characteristics and thus, has been widely used; but LiCoO2 has low stability during high-rate charge and discharge.
Accordingly, developments for new material substituted with the positive active material having shortcomings related to electrochemical performance and stability have been actively made.